Static elements having logical functions



Aug. 18, 1970 J. PESLIER STATIC ELEMENTS HAVING LOGICAL FUNCTIONS 5 Sheets-Sheet 1 Filed July IL .1952

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STATIC ELEMENTS HAVING LOGICAL FUNCTIONS Jacques PEEL/El? Aug. 18. 1910 J. PESLIER 3,524,991

STATIC ELEMENTS mwme mm. FUNCTIONS Filed July 5. .1952 5 Sheets-Sheet s IITI Awewro/r kc acs PESL/ER United States Patent O1 lice 3,524,991 Patented Aug. 18, 1970 ABSTRACT OF THE DISCLOSURE A static element having a logical function characterized by a magnetic inducting C-shaped member whose winding receives the input signals and between the poles of which is located a satura ble magnetic circuit of a monophase transformer whose primary winding is connected to an alternative voltage supply and the secondary winding of which provides the output signals of the logical function, the said primary and secondary windings being located on both sides of the axis joining the poles of the C-rneinbe-r.

BACKGROUND OF THE INVENTION The present invention relates to static elements adapted to be arranged and fed in different manners in order to obtain, individually or in combination, elementary logical operations or a combination of elementary logical operations of the binary variable type having two stable states.

The elements, which are the object of this invention, are particularly remarkable in that they enable to obtain logical circuits of the pure combination type or of the sequential type having a snap-action operation by using a limited number of discrete elements. Another interesting particularity of these elements resides in the fact that they possess an intrinsic security, that is, a. security such that, all defects or changes altering their normal operation, constantly result in a similar output signal which is always interdictive and consequently adapted to eliminate all dangerous situations in a controlled use of these elements. In view of the latter characteristic, they are particularly well adapted, although not exclusively, in traffic signal installations for roads and railways.

SUMMARY OF THE INVENTION According to the invention, these static elements are essentially constituted by a monophase transformer having a saturable magnetic circuit whose primary winding is fed through a resistor, by a source of alternative voltage and whose secondary winding supplies the output signal of the logical function, the saturable magnetic circuit of the said transformer being symmetrically located between the two poles of an inducting magnetic circuit having one or a plurality of parallel cores or branches equipped with coils adapted to be fed by a continuous current, some being connected to voltages taken in the logical circuit constituted by the element or associated elements, the others by the input magnitude of the logical function to create in certain conditions, the change in the state of the magnetic circuit of the transformer and thereafter, the one in the secondary voltage.

In certain cases, the element comprises in addition a magnet mounted in parallel with the terminals of the inducting circuit and (or) another magnet mounted to act on the magnetic circuit of the transformer, in combination with the inducting magnetic circuit.

As it will be more easily understood by the detailed description of some examples of the embodiment and the use of the elements involved in the invention, the logical functions are obtained by the latters due to the siutable choice of the direction and of the value of the flux produced in the transformer by the inducting coils and eventually the permanent magnets, these diiferent parameters acting in combination. to saturate or desatura'te the magnetic circuit of the transformer, that is, to obtain at the terminals of the secondary winding, an alternative voltage which is nill or well defined.

BRIEF DESCRIPTION OF THE DRAWINGS The following description will refer to the drawings wherein:

FIG. 1 is an element whose operation is comparable to the one of a relay of the resting contact type;

FIGS. 2A to 2B are elements associated with two coiled inducting branches for obtaining different logical functions;

FIGS. 3A to 3B are elements arranged with two inducting branches, one being constituted by a permanent magnet,

FIG. 4 is an element whose operation is comparable to the one of a relay of the open contact type;

FIG. 5 is a self-excitation logical element;

FIG. 6 is a diagram representing two associated logical elements having complementary outputs;

FIG. 7 is a diagram representing a timing logical element;

FIG. 8 is a diagram representing a logical element operating with a null transition zone.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The principle of the operation of the logical elements according to the invention, will now be described in details while considering the case of an equivalent element having an electromagnetic relay of the close contact type, that is, whose contact is closed when the coil of the relay is not excited. Such an element is represented on FIG. 1. It consists of a transformer T fed by an alternative voltage U,, through a resistor R, and whose magnetic circuit is located, while reserving a double air gap of a predetermined value, between the poles of an inducting circuit M equipped with a control winding a adapted to be fed by continuous voltage U the latter voltage constitutes the input value of the considered element whose output signal is picked up at the terminals 3 and 4 of the secondary winding of the transformer T to feed a load S. The control winding a being not energized, an alternative voltage is supplied by the secondary winding of the transformer, to the load S. A continuous voltage U,,, having a certain polarity, applied to the winding a, feeds in the magnetic circuit M, a flux which circulates, for example, in the indicated direction by the arrows and saturates the magnetic circuit of the transformer T, whose nature and section are consequently determined. The alternative current absorbed increases and all the alternative voltage U is transferred on the resistance R; the voltage reaching at the terminals 3 and 4 becomes substantially null.

Considering the relation between the states of the binary variables at the input (applied voltage to the control winding a) and to the output (applied voltage to the load S), the logical element represented on FIG. 1 may be considered equivalent to an electromagnetic relay of the close contact type, that is, with closed contact when the coil of the relay is not excited. It enables to obtain the logical function NOT because:

They may be deducted from the same operating principle and differ only by the constitution of the inducting 3 circuit. The description and the drawings will be simplified by grouping the resistance R, the transformer T and the load S under the same symbol TS.

In FIGS. 2A to 2B, the inducting circuit comprises two magnetic branches each equipped with one or two inducting windings, which develop, when they are energized, a flux of the same value which is oriented in the direction of the arrows. As it is known, with such a magnetic coupling, the flux will pass in TS and will cancel the output value only if the fluxes created in each of the branches, are substantially equal and converging.

In view of the above statement, the different diagrams represented in FIG. 2 enable to obtain the logical functions described in the following equations of the Boolean algebra:

FIG. 2A

S=E+b FIG. 2B

Q-EH4 FIG. 2C

It should be noticed in particular that the diagrams of FIGS. 2A and 2B enable to obtain respectively the logical functions AND and OR inclusive and the one of FIG. 2E, the logical function OR exclusive.

'In the case where the output value must be modified only by applying a control voltage of a determined polarity, elements analogous to the preceding ones are used, but wherein one of the branches of the inducting circuit is constituted by a permanent magnet.

FIGS. 3A to 3B illustrate in a n'on-limitative way, some logical functions which may be obtained with elements constituted with a NS magnet producing a flux directed along the direction of the arrows. These functions may be represented by the following equations:

FIG. 3A

S=E FIG. 3B

S'=E-E All the previously developed considerations are based on the use of static elements whose output is equal to 1 in the absence of any control voltage. An operating arrangement will now be described in which an element operating in an analogous manner but wherein the output is normally equal to 0 in the absence of any control voltage (S=a), that is, an element whose operation may be compared to a relay of the open type. It will become possible with these elements to detect a break in one of the control circuits.

A static element according to the above statement, is represented in FIG. 4. Such an element is arranged as the one in FIG. 1, except that it comprises, in addition, a permanent magnet NS whose poles are inserted, while reserving appropriate values for the air gaps, between the ones of the inducting circuit and the magnetic circuit of the transformer T; the latter is consequently saturated in the absence of a continuous control voltage U,, from which results, in these conditions, a substantially null alternative voltage on the load S. The control winding a being energized, a flux having an apposite direction desaturates the magnetic circuit of the transformer T by deriving the flux of the magnet NS and for a determined value of the continuous current circulating in the Winding a, the potential between terminals 3 and 4 tends toward the nominal value corresponding to the transformation ratio. The saturation of the outer magnetic circuit M approximately equals 80% of the nominal control voltage,

which provides the element with a stable operation independently of the temperature and voltage variations.

The various logical diagrams set forth for the close contact element of FIG. 1 and which are illustrated in FIGS. 2A to 2B and 3A to 3B, are equally valid for the open contact element illustrated in FIG. 4, with the exception of the OR diagrams, because the presence of the magnet NS requires a direction to the control magnetic flux. The diagrams of FIGS. 2A to 2D and 3A to 3B applied to open elements consistent with the one of FIG. 4, leads to logical functions which may be expressed such as the ones already mentioned for the close elements.

As an example for the use of these elements, in sequential circuits, a self-excitation element is first described wherein the output must be maintained in the state following an impulsion of the control current.

The logical element corresponding to this application is represented in FIG. 5. It is of the open type, that is with a magnet NS and its inducting circuit comprises two branches on which are applied, on one hand, two windings a connected in series, and on the other hand, two distinct windings c and d, the latter being connected to the secondary winding of the transformer T through a rectifying bridge P. The fluxes produced by these various windings are substantially equal and of the same direction as indicated by the arrows. By means of a striction I, the desaturation flux of the magnetic circuit of the transformer T is limited to the one produced by the addition of the windings a or c+d.

The winding c is previously energized by a direct current; in order to energize the load S, a voltage impulse U is transmitted to the winding a and the fluxes so produced in the two branches by the windings a and c converge on the transformer T and eliminate the magnetizing action from its magnet NS; a voltage appears at the terminals of the secondary winding of the transformer T, the winding d and the load S are simultaneously fed and this feeding maintains itself, after the suppression of the volttage impulse, due to the demagnetizing action of the converging flux produced by the windings c and d. In order to bring the load S to a 0 state, it is sufiicient to break the current in the winding 0, the residual flux produced by the winding d being closed by the left-hand branch of the inducting circuit.

From the preceding explanations, it results that the element illustrated in FIG. 5 enables to obtain the logical function S:aV(dc) FIG. 6 illustrates a second example of a logical sequential circuit which it is possible to obtain with the elements according to the invention. It is a circuit with complementary outputs comprsing an open element associated with a close element, in order to obtain an operation comparable to the one of a translator contact relay enabling, with only one control, to feed one load or another without overlapping.

This circuit which is shown in FIG. 6 is essentially composed of: an open element TA comprising as such, a permanent magnet NS, a close element RE, a load S fed through a rectifying bri lge P by the secondary winding of the transformer T or the elment TA, and a load S fed through the bridge T by the secondary winding of the transformer T of the element RE. On the inducting circuit of the open element TA, there are located two windings a and b whose ampere-turns are equal and opposite. The winding a is inserted in the circuit of the load S the winding b is coupled in series with the winding 0 mounted on the inducting circuit of the element RE; the windings b and 0 may be ifed through a control continuous voltage U In the absence of the control voltage U the load S is not fed because the magnetic circuit of the transformer of the element TA is saturated by the magnet NS; consequently, the primary winding of the transformer of the element RE which is coupled in series with the one of T under the alternative voltage U picks up practically all this voltage and a continuous current circulates in the load S and in the winding a. As it is shown by the arrows, the flux produced by the winding a, increases the magnetizing action of NS on the magnetic circuit of the transformer of the element TA.

When the control voltage U is applied, the transformer T becomes saturated, the current in the winding b tends to decrease the saturation of the transformer T but the ampere-turns of b being equal to those of a the desaturation becomes effective only when the current in the winding a (in other words in the load S is substantially null. At this moment, only the alternative voltage U is practically all brought back on the element TA and the voltage is applied to the load 5 The break in the current of the control circuit immediately leads to the one in S and transfers the alternative voltage of the element TA to the element RE by progressively establishing current in S In the two cases considered above, the passage of a current from one load to the other is therefore guaranteed without overlapping. When a condenser C is connected to the terminals of the winding a, the transfer time from one load to another may be increased.

For the emb doiments requiring a delayed action of about A second between the moment the current is emitted and the one of the change of state of the output voltage, it is possible to use elements of the above-described type in which one of the branches of the inducting circuit will be equipped with a conducting ring closed on itself, this addition resulting, as it is known, in a delay in the establishment of the flux.

If the delayed action must still be more increased, it can beprovided by an integrated condenser, as for example in -a control circuit such as the one illustrated in FIG. 7.

The element considered for this use is an open element TA having a normally saturated transformer by a magnet NS. The secondary winding of this transformer is adapted to lead to a load S and through a rectifying bridge P on a winding b located, as well as a control winding a on the inducting magnetic circuit of the element TA.

The ampereturns of the windings a and b are concordant as shown by the arrows; they substantially have the same value; the inducting magnetic circuit is dimensionedto be saturated when the flux reaches the one produced either by the winding a or b.

A soon as a continuous voltage U is applied to the control circuit, a condenser C is loaded through a resistor R under a voltage which energizes a unijunction transistor UJ when it reaches approximately /a of the supply voltage U the delivered impulse by this transistor UJ makes the thyristor Th conducting in such a way that a condenser C which was loaded through the resistor R (the time constant of C R being slightly lower than the one of C R unloads itself on the control winding a whose ampere-turns have a tendency to produce a feedback flux in the transformer with the one of the magnet NS; a voltage appears at the terminals of the secondary winding of the transformer of the element TA whose primary winding is fed under an alternative voltage U,,; this secondary voltage feeds the load S and through the bridge P, the winding b whose ampere-turns keep the logical element TA in a self-excitation state when the voltage U disappears. It is possible to break the current in the load S by causing a break in the circuit of one of the windings of the transformer.

When the variation of the output current of the abovernentioned elements is studied in relation with the control ampere-turns, it may be verified by experiments that the curve representing this function illustrates, as desired, two plateaux corresponding, one to the control ampere-turns lower than a certain value AT the other to the control ampere-turns higher the value AT with a progressive transition from one plateau to the other when the ampereturns pass (from AT to AT or vice versa, but the difference between AT and AT is not completely negligible and, consequently, a zone of control ampere-turns exists where-in the operation of the element is, due to a lack of stability of the output value in a limited zone, incompatible with the obtention of certain performances. Therefore, an accidental reduction of the control ampereturns AT may lead to an indefinite value at the output.

In order to reduce the above-mentioned instability zone to a negligible value, it is possible, according to the invention, to include on the iniducting magnetic circuit, a reaction winding fed by the rectified current circulating in the load and eventually to utilize for this inducting magnetic circuit a strongly residual material provided with a de'magnetizing supplementary winding.

A logical element having the above-mentioned characteristics is illustrated in FIG. 8. It comprises an inducting magnetic circuit M and a magnetic circuit having a permanent magnet NS between the poles of which is located a transformer T whose primary winding is energized by a voltage U through a resistor R. The secondary winding of this transformer is connected to a rectifying bridge P and the rectified voltage is applied to a load S in series with a feed back winding m.

In the case where such an element is used for the same logical function than the one of FIG. 4, that is, the function of a relay of the open contact type, the flux produced by the control winding a and by the feedback winding m are additional, and the element operates in the following manner: as long as the ampere-turns in the winding a have not reached a certain value, the magnetic circuit of the transformer T is saturated and a very weak current circulates in the winding m, the said weak current being called residual current and corresponding to the re duced voltage which appears at the terminals of the primary winding of the transformer T; when the sum of the ampere-turns produced by the windings a and m reaches the value which starts to desaturate the magnetic circuit of the transformer T, the current in the winding m increases and even if the current in the winding a remains constant, a cascading phenomenon is produced to quickly rock the element and to normally feed the load S well before the current in the winding a has reached the value which would have caused this rocking action.

Such an operation will be stable if the slope of the straight line representing the output current in relation with the ampere-turns of the winding a is higher than the one representing the same current in relation with the ampere-turns of the winding m; the return of the element into its original state by the elimination or the reduction of the current in the winding a will be as quickly guaranteed.

Due to the presence of the winding m, the non-operating zone of the element is reduced in relation to the ampere-turns of the control winding a and, consequently, the speed of the passage from the state 0 to the state 1 is increased at the output of the element.

In order to obtain with an element of the close type, such as the one shown in FIG. 1, a similarly clear operation, the diagram shown in FIG. 8 will be selected for an open cont-act element, that is, which will be equipped with a permanent magnet, but, in this case, the reluc tances of the various branches will be determined so that the flux of the magnet NS, acting separately, does not completely saturate the magnetic circuit of the transformer T and the winding a will produce in the magnetic circuit M a flux opposed to the one of the magnet. The direction of the flux is indicated by the arrow in dotted lines.

In these conditions, in the absence of a control current in the winding a, as soon as an alternative tension U is applied, the magnet NS does not sufficiently actuate the magnetic circuit of the transformer T to prevent the circulation of a rectifying current in the feedback winding m, and as this current tends to cancel the effect of the effect of the magnet NS on the magnetic circuit of the transformer T, it initiates the quick rocking of the logical element under consideration from the state to the state 1.

If, when the element is in a state 1, antagonistic or opposite ampere-turns to the ones produced by the feedback winding m, are produced in the control winding a, as soon as the resulting flux in the magnetic circut M takes the direction of the arrow shown in dotted lines, the action of the magnet NS on the magnetic circuit of the transformer T is reinforced and this reinforcement is increased because it produces, by saturating the said magnetic circuit, a reduction of current in the feedback winding in. The element quickly rocks from state 1 to state 0; the rocking zone 'is null and the operation is stable if the conditions mentioned in the description of the close element for the slopes of the inducting windings are equally adhered to.

In the applications where it is indispensable to use a memory element, that is an element whose state remains after the control current has been broken or in the case where the supply of the alternative voltage disappears, it is possible to produce, according to the invention, the magnetic circuit M in a strongly residual material in which a part of the magnetism remains after the elimination of the control current; this magnetic circuit M then comprises a compulsory supplementary winding dimensioned to create an antagonistic flux adapted to eliminate the residual magnetism.

It should be understood that the invention is not limited to the above-described examples; for example, it is within the scope of the invention to realize logical elements having more than two inputs (or branches of the inducting circuit), operating according to the principle of the elements described above.

I claim: 1. A static element arrangement to be energized so as to perform a logic function on binary variables having two stable states, comprising:

an inductive magnetic device having two poles, an air gap between the poles, and one or plural input windings;

monophase transformer having a saturable magnetic circuit symmetrically located in the air gap of the inductive magnetic device, said transformer having a primary winding fed through an impedance by a source of alternating voltage and a secondary winding adapted to produce an output signal of the logic function performed by said static element, said primary and secondary windings being located on the saturable magnetic circuit of the transformer and positioned one on each side of the axis of the poles of the inductive magnetic device.

2. A static element as defined in claim 1, wherein the inductive magnetic device comprises one or plural parallel cores, each core being provided with one or plural inductive windings adapted to be energized by a source of continuous voltage.

3. A static element as defined in claim 1, wherein the inductive magnetic device comprises at least two parallel cores, wherein at least one of said cores is provided with at least one winding adapted to be energized by a source of continuous voltage, and wherein at least one of the other cores consists of a permanent magnet.

4. The combination of a first and a second static element as defined in claim 1, in which the inductive magnetic device of the first static element has a single core provided with a single winding, and in which the inductive magnetic device of the second static element has a single core with two windings and a permanent magnet sep- :arating the windings of the transformer one winding of the inductive magnetic device of the second static element being connected in series with the single winding of the inductive magnetic device of the first static element and being energized by a continuous voltage, the other winding of the inductive magnetic device of the second static element being energized by a rectified voltage of the secondary winding of the transformer of the first static element and being in series with the output circuit of said first static element, the flux produced by each of the windings of the inductive magnetic device of the second static element being in opposite direction.

5. A static element as defined in claim 1, further comprising a second magnetic circuit associated with a permanent magnet located in the air gap between the transformer and the poles of the inductive magnetic device.

6. A static element as defined in claim 5, wherein the inductive magnetic device has one core provided with two windings, one of said windings being energized by the rectified output voltage originating from the secondary winding of the transformer and connected in series with a secondary circuit which provides the output signal of the logic function, and the other winding being energized by a continuous voltage, the flux produced by each of said two windings being in the same direction.

7. A static element as defined in claim 1, wherein said magnetic circuit comprises two cores holding the primary and secondary windings and wherein a permanetn magnet is located between the two cores of the magnetic circuit.

8. A static element as defined in claim 7, wherein the inductive magnetic device has two cores in parallel, each core having two inductive windings, one winding of one of said cores being connected in series with one winding of the other core and said series connected windings being energized by a source of continuous control voltage, the third winding being energized by a continuous voltage and the fourth winding being energized by the rectified alternating output voltage of the secondary winding of said transformer.

9. A static element as defined in claim 7, wherein the inductive magnetic device has a single magnetic core having two windings, one being energized by a continuous voltage through a timing circuit and the other being energized by the rectified output of the secondary winding of the transformer, the flux produced by each of said two windings being approximately equal and in the same direction.

10. A static element as defined in claim 9, wherein said timing circuit comprises a transistor, means to delay the conduction of said transistor when a control impulse is applied thereto, a thyristor connected in parallel with said one winding of the inductive magnetic device and adapted to be fired by said transistor, a capacitor in series with said one winding and adapted to be discharged through said on winding when the thyristor is fired.

References Cited UNITED STATES PATENTS 3,235,744 2/1966 Webb 340174 1,739,579 12/1929 Dowling 340174 3,275,842 9/1966 Baycura 240-174 3,428,822 2/1969 Demeur 340-l74 BERNARD KONICK, Primary Examiner G. M. HOFFMAN, Assistant Examiner US. Cl. X.R.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No 3, 524 ,991 August 18 1970' Jacques Peslier It is certified that error appears in the above identified patent and that said Letters Patent are hereby corrected as shown below:

In the heading to the printed specification, lines 4 and S, "Societe de Constructions Electromecaniques," should read Societe de Constructions Electromecaniques Jeumont- Schneider,

Signed and sealed this 23rd day of March 1971.

(SEAL) Attest:

EDWARD M.PLETCHER,JR. WILLIAM E SCHUYLER, JR.

Attesting Officer Commissioner of Patents 

